1. Field of the Invention
This invention relates to a method for the production of a semiconductor device and more particularly to a method for the production of a semiconductor device which includes a step for growing a metal film on a dielectric film.
2. Description of the Prior Art
The techniques for forming a dielectric film are broadly divided into physical methods and chemical methods. The physical methods include vacuum evaporation method, sputtering method, and ion plating method and the chemical methods include CVD (chemical vapor deposition) method, sol-gel method, liquid-phase epitaxial method, thermal spraying method, fine particle sintering method, and melt rapid quenching method.
For the film of oxide dielectric substance grown by such method to retain fine quality, it is necessary to preclude the deficiency of oxygen which causes leakage current in the film. For the replenishment of the dielectric film with oxygen, the method of thermally oxidizing the film or exposing the film to oxygen plasma is available.
The techniques for the formation of a metal film destined to function a wiring on the dielectric film include physical methods and chemical methods.
It is the sputtering method that represent the physical methods. The sputtering method consists in colliding a gas ionized in glow discharge against a target made of a component material for a thin film desired to be formed thereby forcing the target to eject particles and inducing deposition of the ejected particles on a substrate.
It is the CVD method that represents the chemical methods to deposite metal. The CVD method consists in introducing that of the compounds of component elements of a thin metal film expected to be formed which fits gasification into a high temperature furnace and enabling the introduced compound to grow a film on the surface of a substrate by dint of a relevant chemical reaction. This method ensures production of a film of crystals of still better quality because it forms the film in a state of equilibrium on the surface of a substrate.
In the field of semiconductor devices, the CVD method has been popularized in recent years because the advance of integration of circuits and the adoption of three-dimensional capacitors have come to demand a film-forming method excelling in coverage.
Most of the CVD methods for forming a metal film are carried out in a reducing or deoxidizing atmosphere and, therefore, have the possibility of extracting oxygen from the underlying film of oxide dielectric substance. This phenomenon tends to cause either degradation of dielectric constant or deterioration of crystals and high leakage current.